Apps and product development is like a marketplace now, the demand for software is huge but most people just don't know about what they can do with software. So there are hundreds of GPT Excel's out there, but there is demand for thousands so if you can do this in one week, do it! There is a lot of people trying those projects just for fun and spending money on it.
Frankly, and I don't want to downplay anybody's work, but this seems doable. The core engine based on API calls to OpenAI is probably a few hours. The remaining time is for user authentication, subscriptions, payments, graphics and so on.
I know this because I'm using OpenAI API for personal automation projects and in spite of its quirks it's relatively simple especially if you don't need continuity and each task is independent.
> Not sure if everyone knows just how easy making something like this is. This kind of an app takes less than one week to develop, using the OpenAI function calling API.
So - the original statement was "something like this". Not the design, the videos, the templates but the core, essential functionality. And that is probably a couple of hours work.
I suspect the real value is mainly in the prompt templates. I haven't tried but there's probably some wording that helps guide the results. It might be that these took a lot of trial and error to tune - or it might be that the first thing I try gives me results as good as GPTExcel.